1 files changed, 117 insertions, 0 deletions
diff --git a/grub-core/disk/memdisk.c b/grub-core/disk/memdisk.c
new file mode 100644
index 0000000..114ac0d
--- /dev/null
+++ b/grub-core/disk/memdisk.c
@@ -0,0 +1,117 @@
+/* memdisk.c - Access embedded memory disk.  */
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2007,2008  Free Software Foundation, Inc.
+ *
+ *  GRUB is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  GRUB is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <grub/disk.h>
+#include <grub/dl.h>
+#include <grub/kernel.h>
+#include <grub/misc.h>
+#include <grub/mm.h>
+#include <grub/types.h>
+
+GRUB_MOD_LICENSE ("GPLv3+");
+
+static char *memdisk_addr;
+static grub_off_t memdisk_size = 0;
+
+static int
+grub_memdisk_iterate (int (*hook) (const char *name))
+{
+  return hook ("memdisk");
+}
+
+static grub_err_t
+grub_memdisk_open (const char *name, grub_disk_t disk)
+{
+  if (grub_strcmp (name, "memdisk"))
+      return grub_error (GRUB_ERR_UNKNOWN_DEVICE, "not a memdisk");
+
+  disk->total_sectors = memdisk_size / GRUB_DISK_SECTOR_SIZE;
+  disk->id = (unsigned long) "mdsk";
+
+  return GRUB_ERR_NONE;
+}
+
+static void
+grub_memdisk_close (grub_disk_t disk __attribute((unused)))
+{
+}
+
+static grub_err_t
+grub_memdisk_read (grub_disk_t disk __attribute((unused)), grub_disk_addr_t sector,
+		    grub_size_t size, char *buf)
+{
+  grub_memcpy (buf, memdisk_addr + (sector << GRUB_DISK_SECTOR_BITS), size << GRUB_DISK_SECTOR_BITS);
+  return 0;
+}
+
+static grub_err_t
+grub_memdisk_write (grub_disk_t disk __attribute((unused)), grub_disk_addr_t sector,
+		     grub_size_t size, const char *buf)
+{
+  grub_memcpy (memdisk_addr + (sector << GRUB_DISK_SECTOR_BITS), buf, size << GRUB_DISK_SECTOR_BITS);
+  return 0;
+}
+
+static struct grub_disk_dev grub_memdisk_dev =
+  {
+    .name = "memdisk",
+    .id = GRUB_DISK_DEVICE_MEMDISK_ID,
+    .iterate = grub_memdisk_iterate,
+    .open = grub_memdisk_open,
+    .close = grub_memdisk_close,
+    .read = grub_memdisk_read,
+    .write = grub_memdisk_write,
+    .next = 0
+  };
+
+GRUB_MOD_INIT(memdisk)
+{
+  auto int hook (struct grub_module_header *);
+  int hook (struct grub_module_header *header)
+    {
+      if (header->type == OBJ_TYPE_MEMDISK)
+	{
+	  char *memdisk_orig_addr;
+	  memdisk_orig_addr = (char *) header + sizeof (struct grub_module_header);
+
+	  grub_dprintf ("memdisk", "Found memdisk image at %p\n", memdisk_orig_addr);
+
+	  memdisk_size = header->size - sizeof (struct grub_module_header);
+	  memdisk_addr = grub_malloc (memdisk_size);
+
+	  grub_dprintf ("memdisk", "Copying memdisk image to dynamic memory\n");
+	  grub_memmove (memdisk_addr, memdisk_orig_addr, memdisk_size);
+
+	  grub_disk_dev_register (&grub_memdisk_dev);
+	  return 1;
+	}
+
+      return 0;
+    }
+
+  grub_module_iterate (hook);
+}
+
+GRUB_MOD_FINI(memdisk)
+{
+  if (! memdisk_size)
+    return;
+  grub_free (memdisk_addr);
+  grub_disk_dev_unregister (&grub_memdisk_dev);
+}